NONLINEAR PHARMACOKINETICS OF FLUVOXAMINE AND GENDER DIFFERENCES

This prospective study assessed fluvoxamine serum concentrations under two different fixed doses. The study included 15 male and female pati ents who met the DSM-III-R criteria for major depression. They were pr escribed 50 mg fluvoxamine twice a day for 2 weeks and 100 mg twice a day thereafter. Drug monitoring was carried out on days 14 and 28. Flu voxamine serum concentrations were highly variable between patients. A fter the dose was doubled, the serum concentrations of fluvoxamine inc reased disproportionately (mean, 3.4-fold), and there was a significan tly (p < 0.05) more pronounced increase in men (4.6-fold) than in wome n (2.4-fold). These results provide evidence of nonlinear, sex-depende nt pharmacokinetics of fluvoxamine.